Declare objects globally or pass as parameter in Package

Question

Hi All,
Need a technical suggestion, in a package i am having several functions,
say Fn_A calling Fn_B and Fn_B calling Fn_C and Fn_C calling Fn_D
and i need a collection of Nested Table Objects to be processed at Fn_D,
and it has to reach from Fn_A, in-between say Fn_C if required, can also process
the Nested Table Object.
Also for each Function need to pass 3 parameters of collection object and 3 to 4 Number/Varchar2.
My question is, would it be better to declare the Nested Table Object globally inside the package,
or Pass it as an IN OUT NO COPY parameter throughout all functions ?
And the scenario is :
Nested Table would have 1000 objects in the collection,
and each object will have size = 75 Bytes
and in one day on an average 3 million calls made.
regards,
Ludy

Answer 1

My bias would be not to use a package global if you can reasonably pass the collection as a parameter. It's easier to maintain code that is self-contained rather than trying to debug code whose behavior depends on the state of the session. If you pass in the collection as a parameter, you can write unit tests for all 4 procedures relatively easily rather than having to go through all 4 to test procedure D. Plus, if you don't need to maintain session state, you can update your package code without causing any application tier connections that remained open to error out.
Performance wise, I wouldn't expect it to matter, though it would be worth benchmarking.
Justin